fn: rename from fnctl (#321)

* fn: rename from fnctl

* fn: predicting the release version for installer

* fn: predicting the release version for installer

docs/lambda/test.md

@@ -11,7 +11,7 @@ docker run
 
 An example of a valid `test-function` command would look as follows:
 ```
-fnctl lambda test-function user/my-function --payload='{"firstName":"John", "lastName":"Yo" }'
+fn lambda test-function user/my-function --payload='{"firstName":"John", "lastName":"Yo" }'
 ```
 
 ## Payload